Low fuel run to impress potential sponsors or not, the Brawn GP had circulated the Barcelona layout in an unofficial 1min19.1.

Even the cynics were astonished when Jenson Button cut the timing beam on the Circuit de Catalunya pit straight on Wednesday.

Low fuel run to impress potential sponsors or not, the Brawn GP had circulated the Barcelona layout in an unofficial 1min19.1.

Last April for the Spanish grand prix at the same venue, Robert Kubica's BMW was the fastest car in the low-fuel Q2 phase -- a 1min20.5.

"If it stays like this, Brawn GP will be all by themselves at the front in Melbourne," Sebastian Vettel marvelled to Germany's Auto Motor und Sport.

Likewise, Fernando Alonso on Wednesday admitted that the BGP001 currently seems faster than his Renault. "Brawn is not such a surprise for me because they have been preparing their car for a long time.

"They have done great work with the aerodynamics," the Spaniard added.

After a similarly impressive Monday and Tuesday in Spain, Button's Mercedes-powered car, fundamentally designed under Honda ownership last year, was a full second and more quicker than the chasing Ferrari, BMW and Toyotas.

At the other end of the spectrum, McLaren's woeful winter continued on Wednesday, Lewis Hamilton slowest of the ten runners and at one point in the barriers at turn 2.

Compounding the 2008 world champion's misery, when he returned to the pits from his crash, the ardent Spanish fans made clear their derision with a shower of boos and whistles.

Referring to the Mercedes-powered MP4-24, Ron Dennis told Reuters Television in London on Wednesday: "It is certainly not as fast as we would like it to be.

"But it's early days and we've still got quite a bit of testing to do and quite a bit of development to reflect through into our pace."